1. Unpack the zip file. Inspect the code to assure yourself I’m doing nothing untoward (it’s good practice for any extension given to you in this manner).
2. Visit chrome://extensions in your Chrome browser.
3. Click “Load unpacked extension…”
4. Select this directory and click OK.
5. Voila! The extension is in place. Click the [j] icon to Jagerise a page.